1. Field of the Invention
The present invention generally relates to a camera and, more particularly, to a camera having a trimming mode selecting function of designating a range narrower than a normal photographic range as a print range, and a hand shake detecting function.
2. Description of the Related Art
Cameras having various types of hand shake preventing means have been proposed. For example, some cameras are designed to generate a warning or stop a photographic operation when a hand shake is likely to occur. In addition, some other cameras are designed to vibrate a photographic optical system in a direction to reduce a shake in order to actively decrease the magnitude of the shake.
In general, when a negative film which has undergone a photographic operation is subjected to a printing/enlarging process by means of trimming, a pseudo-telephoto effects can be obtained with this process, a small image on a negative film can be enlarged and seen as a large image. Therefore, a camera capable of designating a trimming size in a printing/enlarging process or a photographic system capable of handling optical information such as trimming information other than photographic information equivalently has a high-magnification zoom lens, even if it is a single-focus camera, which is a great merit.
For this reason, the following techniques have been developed.
For example, U.S. Pat. No. 4,774,536 discloses a camera which determines an equivalent focal length from a trimming size determined upon a trimming size designating operation, and determines a hand shake shutter speed limit on the basis of this information, thereby obtaining a shutter speed limit in a trimming photographic operation.
In addition, U.S. Pat. No. 4,780,735 discloses a technique of shifting the aperture state from the full-aperture state toward the stopped-down-aperture state and increasing the shutter speed in accordance with a designated trimming level, thereby preventing a photographic operation resulting in an image blur and an out-of-focus state.
Furthermore, U.S. Pat. No. 4,780,735 discloses a technique of detecting ISO film speed information and posing some limitations on the determination of a trimming size, thereby preventing an excessive deterioration in the image quality of a print obtained by a photographic operation using a high-speed film.
Moreover, Jpn. Pat. Appln. KOKAI Publication No. 64-55544 discloses a technique of determining whether a given trimming size falls within the interlocking range of an automatic focusing unit and also determining whether setting of a trimming size on the basis of object brightness information is permitted (setting of a trimming size is not permitted in an out-of-focus state regardless of brightness information).
If, however, a hand shake preventing means is operated, the release time lag or the power consumption is increased, or a warning display and the like in combination with other warning displays are complicated and difficult to recognize. For this reason, it is preferable that the hand shake means be operated only when it is required. However, in a camera to which the above-mentioned trimming mode selecting function is added, it is difficult and cumbersome for ordinary users, except for some skilled users, to select an operation or non-operation mode.
In addition, a user may feel as if the image quality of a print greatly deteriorates, depending on a trimming size in a printing/enlarging process. Furthermore, when an image on a negative film is enlarged by a trimming process, an image blur, an out-of-focus state, and the like on the negative film are also enlarged. Consequently, the resulting photograph may not be as beautiful as the photographer thought.
The following problems are posed in the above-described trimming cameras.
For example, in the camera disclosed in U.S. Pat. No. 4,774,536, since the shutter speed is increased regardless of the state of an actual shake, the shutter speed is unnecessarily increased even if no shake is caused. For this reason, the resulting photograph may have a small depth of field, or an electronic flash may unnecessarily emit flashlight.
In addition, in the camera disclosed in U.S. Pat. No. 4,780,735, since the aperture value and the shutter speed are changed in accordance with a trimming level, exposure conditions are undesirably limited regardless of the presence/absence of an image blur and an out-of-focus state.
Furthermore, in the camera disclosed in U.S. Pat. No. 4,780,735, although no problems are posed in the use of a high-speed film, no specific limitations are set in the use of a generally used low-speed film, disregarding actual photographic conditions.
Moreover, in the camera disclosed in Jpn. Pat. Appln. KOKAI Publication No. 64-55544, the determination of permission/prohibition of a trimming photographic operation is performed simply on the basis of object brightness information, regardless of a trimming size, so that the determination varies in an actual operation with a slight brightness change. Such an unnatural operation will confuse the photographer.